//构造函数
function Person(name,chinese,math){
      this.name=name
      this.chinese=chinese
      this.math=math
      this.fn=function(){
          return "name:"+this.name
      }
      this.fn1=function(){
        return "chinese:"+this.chinese
    }
    this.fn2=function(){
        return "math:"+this.math
    }

}

function Student(name,chinese,math,age){
   this.age=age
   Person.apply(this,[name,chinese,math])
   this.fn=function(){
    return `姓名：${this.name}<br/>语文：${this.chinese}<br/>数学：${this.math}<br/>年龄：${this.age}`
   }
   
}

//创建对象
let p=new Student("张三",98,80,25)
app.innerHTML=p.fn()